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ABSTRACT: A crucial issue of civilian applications of ad-hoc networks is cooperation of nodes. More precisely, each node has its own authority and may try to maximize the benefits it gets from the network without participating to its services (e.g. without forwarding packets of other nodes). To conquer with this problem, a virtual currency, namely nuglet (Buttyan and Hubaux, 2003), is used to provide an incentive for cooperation by having a node to send its traffic at a given cost, while allowing it to profit every time it forwards others' traffic. Several papers have shown that such a model encourages individual node cooperation. In this paper, we consider a network whose nodes use nuglets except that when a node empties out of nuglets, as a penalty and to enforce more cooperation, it can not forward its own traffic again until forwarding K packets of other nodes. Once the node begins to send its own packets, it proceeds normally until the node becomes empty again. We develop a Markov model of the network to evaluate the system performance in terms of network capacity, data generation delay and the probability that a node empties out of nuglets. We use these performance parameters to show that how the proposed scheme encourages nodes to cooperate with the network. We also show the trade-off between increasing node cooperation and data generation delay and analyze it by defining a total cost function due to non-cooperative behavior and data generation delay. At last, a comparison between our scheme and the scheme proposed in the work by Buttyan and Hubaux (2003), as the most well-known protocol in node cooperation schemes, is presented.
Vehicular Technology Conference, 2008. VTC Spring 2008. IEEE; 06/2008
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ABSTRACT: Information technology (IT) is an important component in organization's competitive advantages. IT services directly effect on business processes and organizations success. It is essential to adapt the IT function with business objectives and priorities, and work toward the optimization of IT resources globally for higher performance of the organization. Most companies spend too much time for determining how much money to spend on IT and not enough time determining how to manage and allocate their IT spending in any part of business processes. Seeking high-performance results from the use of IT is very important for business executive managers and information technology managers in every organization. In this paper a practical approach for measuring the amount of IT effectiveness on business processes by using a fuzzy approach that is known as MADM (multiple-attribute decision making) has been proposed. The amount of this metric enables managers to discover exactly where business performance improvement opportunities lie and finally elevates IT function to its rightful place in organizations.
e-Business Engineering, 2007. ICEBE 2007. IEEE International Conference on; 11/2007
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ABSTRACT: In this paper, we investigate a clustering protocol for single hop wireless sensor networks that employs a competitive scheme for cluster head selection. The proposed algorithm is named EECS-M that is a modified version to the well known protocol EECS where some of the nodes become volunteers to be cluster heads with an equal probability. In the competition phase in contrast to EECS using a fixed competition range for any volunteer node, we assign a variable competition range to it that is related to its distance to base station. The volunteer nodes compete in their competition ranges and every one with more residual energy would become cluster head. Our objective is to balance the energy consumption of the cluster heads all over the network. Simulation results show the more balanced energy consumption and longer lifetime.
Computer Systems and Applications, 2008. AICCSA 2008. IEEE/ACS International Conference on;
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ABSTRACT: This article introduces an event driven data reporting and routing algorithm for wireless sensor networks that offers a local timing based data reporting scheme in a clustered network. When an event occurs, the nodes that has discovered the event, are supposed to report it to their respective cluster heads. All of these nodes would wait for a specific time (based on its residual energy) to send the information. However, only the one of the sensing nodes is going to send the data to the clusterhead. The most appropriate node is the one with more residual energy and it will take its tour sooner to report the data. The waiting time for each individual node is based on its residual energy and its respective cluster head's energy. A channel access management based on CSMA is used for avoiding collision and multiple sending. The performance of this algorithm is evaluated in the sense on network lifetime and event detection reliability.
Computer Systems and Applications, 2008. AICCSA 2008. IEEE/ACS International Conference on;
